Performance of electromechanical components such as those of computer disk drives has been found dependent substantially upon the properties of the component materials. For instance, to accurately pass data to and from the disk, it has been found necessary to precisely align transducers on the actuator armset with tracks on the disk. When the temperature of the disk drive rises, as is common during operation, the armset expands, interfering with the transfer of data to and from the disk. It is therefore desirable that the armset be constructed of materials having nominal coefficients of thermal expansion, i.e., which expand minimally when subjected to increasing temperatures.
To insure quick and precise armset movement using minimal power, it has also been found necessary to use light weight materials so that the forces of inertia exerted by the armset may be reduced. By using low weight (density) materials, the armset's moment of inertia is reduced, disk drive performance is improved, and power consumption minimized.
In addition, materials are desired which have both a high stiffness to mass ratio and high resonant frequency. This provides the armset with the strength to withstand the frequent sudden movements typically experienced during disk drive operation, while minimizing armset vibration and settling time.
Materials such as silicon carbide and aluminum-beryllium alloys have been found beneficial for their low thermal expansion, high stiffness and resonant frequency. Although useful, their relatively high density (weight) has made them less desirable. Beryllium and alloys of magnesium also have advantages, but none combine the benefits of high stiffness and resonant frequency with low weight, thermal expansion and cost.